Stuffing-box packing



Jan 13 1931-@ F; E. sMlTH ETAM.V "sTUFFNGBoX PACKING V Filed .1330."26, 1925 l i SSLIREl OI L M E T s v.. S

Patented Jan. 13, 1931 'l Tron, OF sYEAOUsE, NEW Yoan, A CORPORATION OE NEW YORK f '-'s'rUEEING-EOX EACKING l Application ledfDeceniber 26, 1925, Serial No. 77,884, and in nGreat.BritainDecember 29, 1924.

This inventionrelat-es to packing material, andinore particularly to, an improved metallic packiiiginaterial 'for use in arstuiing box and involving novel methods of adjust'- inent. i' l The ordiiiarytype; of metallic glandpaclb ing` consists of-rings of such a section that, a fiat surface is presented totherod, and with such packing.` it is not practica-ble to reduce theclearaiice between the bearing surfaces to less than jl/lOOO of an inch on account-of the excessive-wear which occurs with thesel small clearances.` When the said sinallclear-g anees are used, the` packing demands continual attention andl requires periodic reneWal. Moreovei', withthe old type of gland packing the oil distribution.betweenthebear# ing surfaces always tends to become .irregui lar. -As a result of this irregularity'ofV lubrication, heavy` Wear and friction said bearing surfaces. 1

Occur attlie It is an object ofthe present linventionlto 'providea packing for a gland or the like which oifers a negligible frictionalfresistance andundergoes a minimalwear atthe bearing surfaces not only when the gland .y is subjected i to comparatively lowf pressures, but also to comparatively vhigh pressures.` ,n s

It is a furtlierobject of thefinventionto provide a gland `packing-ringiwhicliv has a clearanceles's than l/'lOOO Ofan inch and vvhich is especially. adapted for high pressure Work in gas pumps orl the like to preventgeie cessive leakage of. the fluid therefrom. `The said improved ring issuch that the original shape vthereof may bey L restored .after being flattened by wear simultaneously with the adjustment of the clearance betvveen the said ring and the rod or shaft therein. y f Another Object ofthe invention is to provide ay gland which causes aregulardistribution ofoilon the aforesaid shaft or rod, and ivesan improved uniform' lubrication thereor. Y v Other features andadva'ntagesiof theinvention will be madev clear-bye description of certain referred embodiments thereof, as illustrate in the accompanying drawings. inwhich Fig. l is ayvertical section through an embodiment of our invention; Fig. 2 is a view similar toiFig. l showing a modified embodiment oi' our invention; Fig. 3i-s al seetional elevation of a complete gland having a plurality of our improved rings, as shown lin, Fig. 2, incorporatedtherein; ,-and Fig. 4 lllustrates a-niethodof withdrawing the rings, Generally speaking, our improved packingy ring comprises airaniiularbody portion 1i provided `witlra slotorv'deep groove 2 contiguousto theouter. periphery 3 thereof. The inner peripheryQO has. a slight convex curvature 2l which actsas tthe. bearing sur, face. Any appreciable curvature of the said surface `Will `give beneficial results, but as an example, radii of.2 to 9 may bespeeiied.

` The material of the ring may be any which is sensibly softer than that ofthe shaft, sub-` 1ectof .-course, Vto the particulargdemands of individual cases and conditions of Working temperature andjpressure. Those metals or alloysl wliich-exliibittlie propertiesof bearing or ,aiitifrictioii" inetalspywlll knaturally mimtwice;`

EEANK'EWART sMIcrrr,"oEEIEENGHAMlONfTEEs, AND DONOVAN vvrL'nINerl COLE, OE vNoR'roN-oN-zrEEs, ENeLANnyAssIeNORs 'ro ATMOSPHERIC NITEOGENOOEPOEA-j bebest adapted to` this purpose, for example,

White ine-tal, orbrass, etc., but the use of other metals or alloys is not excluded, sinceaecording -to the invention such efficient lubrication is'attained that t-lieprecisephysieal nature of the bearing surface becomes of lesser importance.A It is not absolutely essential, though generally, itf will. be-tlie ease, that the rings should be of softer material than the shaft. Again, While neither aluminum nor copper isl generall7 ,considered suitable asa bearing metal,` either maybe used Withadvantage,

wlientlie principles ofi'thef present invention and the Wear of the rods is again practically negligible. kConsequently,the use` of copper or aluminum rings maybe resortedto in cir- 'are appliedtothe design ofthel packing rings, y

true bearing metals are used, but still extremel small on account of the almost perfeet 1u rication maintained.

of the said rings have substantially a U:

shaped cross-section so that the composite ring has a deep groove 24 contiguous 'to' the outer peripherythereof. rA bearing surface 25, having'slight convex curvature, is provided on theinner periphery of said' ring.

' By this composite construction, the material strength of thepackin ring and its resistanc'e to deformation un er pressure is greatly improved, the constitution of the-ring being such as to cause-it to oier elastic resistance,

duringl the time that the ring is under compression, to force applied to the sides of'its Uin an axial direction. i

In a simple stuiling box 13 surrounding a member moving through a wall 28 of apressure chamber C, l as a pump P illustrated dia rammatically `in Fig. 3, a numberV of pacing rings 14 similar to the one shown in Fig. 2 are mounted side by side and arefseparated from each other by steel 'cagerings V115. A land nut 12 is adjusted so as to. allow the so tl metalring's 14 just to oat between` the steel cage rings 15. In this state' the `gland remains during working until'a small amount of wear occurson the soft metal rings. The

gland nut v,12 is then tightened up, 'pressing the packin rings andthe walls 'of the'cage rings 'toget er',.and producing a slight'bulge in the said packin rings'on their' curved bearingsurface.- T e'slight bulge is checked by contact'with the stationary shaft'l-O vand then the nut12 isslacked back a trifie. This,

by virtue of the elasticity of the metal,allows the rings to s ring oli the shaft about 1A to 1/2 of a thousan th of an inch (which is just the desiredamountlfor high pressure work) and also fonce moreenablesl the rings to float in their cages. 1

Thel term"oat means that thel packing 'rings are given a slight -freedom of movement-which is suilicient to give an automatic self-centering effect asiwill be explained hereinafter. u

Adjustment after this'manner will prolong indefinitely the lie oa gland packing, and

- at the `sametime` the-gland will maintain its original efficiency` and kthe plunger rod will only wear to minimal extent. `In-actual practice the stuffing boxshown in Fig. 3 will be provided'with two lantern'rings 16 and 19 Y insa-ies functioning respectively as inlet 17 and outlet 18 for the oil supply. It is generally advisable that as little oil as possible should reach the cylinderor chamber C, and, therefore, one or more packing rings 14 may be providedbetweenjthe -lanterni'ings 16 and the cylinder.y -A packing ringfolr rings of the same character as the packing rngs14 may beused between 19 and` the outside of Y the glanditoj prevent extrusion fofv oil.` Any numberof' thep'ackngjring units may be used in series. It will be observed that in assembling the packing rings in the gland stuffing box, the legs of the U-shaped crosssection are ata substantial distance from the wall of the stuffing box or of the cage rings.

15, so that the peripheral edges of the open ends of the-U will always remain and be 'maintained 'spaced'from aphysically abuttingv surface, irrespective of the vdegree of compression to which the rings may be 'subjected, sothat in all positions ofadjustment the packing rings will be able to maintain their floating condition.l l f With the movement of the reciprocating plunger rod-10 of a pump 'P shown in Fig-3" the oil'iscontinually `trapped between the ring and the rod, and the'layer of lubricant between the two 'is consequently maintained intact. Moreover, as va' result of theconvexity of the surfaces, if atany-time during the ref ciprocating motion of the rod, said rod is not 1n the exact center ofthe ring, the oil pressure on the `closer sidelwill exceed thatjon the other, andl equilibrium-will'berestored only when thering takes up the correct posif tion, i e. equidistant at all Apointsvfioi'n ythe rod.V This'sel'f-'adjustinentof the rings, due

essentiallyyto the'convex surface, assists the success of' the lubricating action referred to above, and 'asa result of these twofact'ors, the 'final' wear on the shaft `isexceedingly small.' Any appreciable curvature of the surface will'givebenecial results,but as an example,radii of 2 to 9 may be specified.

l Whendfor any reason itis'lrequired todi'smantle thevland'packind, this-may fbe conveniently eectedas in `igr4 Abyscrewing thinv 'steelrods 9 having threads26 at the ends thereof 'into1s'mall'threaded holes 8, sunk part way 'into the wall of the cage rings 6. l By grasping #and pulling the free ends 27 of Asaid -rodsfthe 'cage rings-6 are'thus easily drawn along l-th'e shaft 7 bringingxthe packing rings fl-witli them."

It yviii be Observe- 1 that the packing-ring of this invention'c'omp'rises an' annulus sub-l stantially U-shapedin every radial cross-section of the annulus','the closed'part ofthe U nearest to the center of the `ring being slightly Vconvex atthe 1 inner periphery of the ring to afford a bearing-surface'at said point. The outer faces-of the legs of the- U have portions located laterally, approximately, of the closedpart of theU and these latth ber,

portions are disposed to receive compressive thrusts and to transmit the effect thereof directly to and through the metal constituting the closed part of the U. When therefore the nut l2 is tightened and compressive thrusts are thereby imparted to the rings in a lateral direction, the eilect is not that of bending the legs of the U toward each other e upper part of the U but to reduce the width of the ring in the region of the closed part of the U, thereby causing the formation of a convex condition at the inner periphery of the ring as the result of the transmission of the compressive thrusts directly to and through the metal constituting the closed part of the U.

While preferred embodiments of our invention are illustrated and described, it is to be understood that variations may be made without departing from the scope and spirit l of the invention.

'lVe claim in said stuffing box and around` said movable member, said ring having a substantially U-shaped cross-section in which the open portion between the legs of said `U is at the outermost periphery of said ring and the closed body portion of the U is at the innermost periphery of said ring, said innermost periphery forming a convex bearing surface making line contact with the aforesaid movable member,

of the closed body portion inwardly toward the center of the ring, said ring being in floating relation with respect to the walls of the stutiing box, whereby said ring may center itself with respect to said movable member.

2. The combination with a 4pressure chamber, a member movable through a wall of said chamber, and a stuffing box contiguous to said .wall surrounding said movable memher, of an undivided packing ring contained in said stufiing box and around said -mov abllimember, said ring having a substantia y open portion between the legs of said U is at the outermost periphery of said ring and the closed body portion of said U` is at the innermost periphery of said ring, the legs of said ring projectingl in parallel relation to each other outwardly from the body portion and extending a sufficient distance to provide substantially parallel bearing faces for compressive elements adapted to transmit compressive forces to the said parallel bearing faces axially of the movable member to cause bulging of the closed body porinnermost periphery of U-shaped cross-section in which thel tion inwardly toward the center of the ring to form l convex bearing surface making line contact with the aforesaid moving member, the outer periphery spaced from the Walls of the stuiiing box, whereby said ring may center itself with respect to said moving member.

3. The combination with a pressure chamber, a member movable through a wall of said chamber, and a stuing box contiguous to said wall surrounding said movable member, of an undivided in said stuffing box and around said movable member, said ring having ay substantially U-shaped cross-'section in which the open portion between the legs of said U is at the outermost periphery of said ring and the closed body portion of the U is at the said ring, said innermost periphery forming a convex bearing surface making line contact with the aforesaid moving member, the exterior of said U-shaped cross-section being composed of a soft metal and the interior being comy posed of a metal having a higher yield point than said soft metal, and compressive elements adapted to transmit compressive forces to the legs of the U to cause bulging of the closedv body portion inwardly toward the center of the ring, said ring being in floating relation with respect to the walls of the stuffing box, whereby said ring may center itself with respect to said moving member.

In testimony whereof we have hereunto set our hands.

F. E. SMITH. D. WILDING COLE.

of the ring being 

